High-Quality Heavy Copper PCB from China Suppliers: High Current Capacity for Power Converters and Vehicles | Factory Direct Quality Manufacturer, Supplier
Product Description
What is Heavy Copper PCB?
Core Features and Application Scenarios
70μm copper foil (2 oz) carries approximately twice the current of 35μm (1 oz) under the same line width.
The thick copper layer rapidly conducts heat, reducing the risk of device overheating.
Thick copper enhances the PCB's resistance to bending and impact.
Power converters (AC-DC / DC-DC), BMS for new energy vehicles, industrial frequency converters, control boards for welding machines, and more.
Key Design Points
Common specifications: 70μm (2 oz), 105μm (3 oz), 140μm (4 oz), and up to 420μm (12 oz) in extreme scenarios.
Matching scenarios: For large current (≥5A) circuits, prefer 2–4 oz copper. For ultra-power scenarios (≥20A), select 6–12 oz copper.
Current-carrying capacity calculation: Thick copper trace capacity is determined by copper thickness, line width, and temperature rise (typically designed for 10℃ rise).
Formula reference: I = K × W × T0.83 (I = current, K = coefficient, W = line width, T = copper thickness).
Example: 2 oz copper (70μm), wire width 5mm → current carrying capacity ≈ 15A (at 10℃ rise).
Trace optimization: Keep high-current traces as short and wide as possible; avoid narrow necks. For multi-layer boards, use "parallel connection of multiple copper layers" (e.g., 2 layers of 2 oz = 4 oz equivalent) to enhance current-carrying capacity.
Vias: For high-current vias, increase hole diameter (≥0.5mm), add more vias (estimate ~1A per hole), and ensure copper plating thickness on hole walls ≥20μm (vs. 8–12μm for standard PCBs).
Pads: Thick copper pads should be enlarged (0.2–0.5mm larger than standard pads) to prevent heat dissipation issues during soldering that may cause false soldering.
Heat dissipation: The thick copper area can be designed as a "copper sheet heat sink," or a metallized via array (via spacing ≤1mm) can be added to connect to the heat dissipation layer.
Insulation: Wire spacing for thick copper layers should be widened (for 70μm copper, spacing ≥0.2mm) to prevent creepage breakdown under high voltage.
Manufacturing Process Difficulties and Control
Thick copper lamination: Requires high-temperature and high-pressure lamination (180℃ / 4MPa) to ensure peel strength between copper foil and substrate (≥1.2 N/mm).
Thick copper etching: Etching rate is slow (~1μm/min); etching time must be controlled to avoid side etching (side etching ≤0.05mm). A stepwise etching process should be adopted to reduce line width deviation.
The coefficient of thermal expansion (CTE) of thick copper layers differs significantly from that of the substrate. During lamination, a "symmetrical structure" (consistent copper thickness between upper and lower layers) should be adopted, and a rigid support layer added to prevent PCB warping (warping degree ≤0.5%).
The surface of thick copper is prone to oxidation. Tin plating (high-temperature tin layer) or nickel-gold plating is preferred; avoid OSP due to incomplete organic film coverage.
The pad area requires an enlarged "solder mask opening window" to ensure adequate bonding force between solder and thick copper.
Core Summary
The core of heavy copper PCBs is "high current-carrying capacity + heat dissipation." In terms of design, it is necessary to match copper thickness with current-carrying capacity requirements. In manufacturing, challenges such as thick copper etching and lamination warping must be addressed. Heavy copper PCBs are best suited for high-power and high-current industrial and energy scenarios.
